Page MenuHomec4science
Files F75089076

fix_lb_viscous.html
No OneTemporary
Actions

File Metadata

Created
Wed, Jul 31, 07:40

fix_lb_viscous.html
View Options

<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>fix lb/viscous command &mdash; LAMMPS documentation</title>
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
<link rel="stylesheet" href="_static/sphinxcontrib-images/LightBox2/lightbox2/css/lightbox.css" type="text/css" />
<link rel="top" title="LAMMPS documentation" href="index.html"/>
<script src="_static/js/modernizr.min.js"></script>
</head>
<body class="wy-body-for-nav" role="document">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-nav-search">
<a href="Manual.html" class="icon icon-home"> LAMMPS
</a>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
<input type="text" name="q" placeholder="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<!-- Local TOC -->
<div class="local-toc"><ul>
<li><a class="reference internal" href="#">fix lb/viscous command</a><ul>
<li><a class="reference internal" href="#syntax">Syntax</a></li>
<li><a class="reference internal" href="#examples">Examples</a></li>
<li><a class="reference internal" href="#description">Description</a></li>
<li><a class="reference internal" href="#restart-fix-modify-output-run-start-stop-minimize-info">Restart, fix_modify, output, run start/stop, minimize info</a></li>
<li><a class="reference internal" href="#restrictions">Restrictions</a></li>
<li><a class="reference internal" href="#related-commands">Related commands</a></li>
</ul>
</li>
</ul>
</div>
</div>
&nbsp;
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="Manual.html">LAMMPS</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="Manual.html">Docs</a> &raquo;</li>
<li>fix lb/viscous command</li>
<li class="wy-breadcrumbs-aside">
<a href="http://lammps.sandia.gov">Website</a>
<a href="Section_commands.html#comm">Commands</a>
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<div class="section" id="fix-lb-viscous-command">
<span id="index-0"></span><h1>fix lb/viscous command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="n">ID</span> <span class="n">group</span><span class="o">-</span><span class="n">ID</span> <span class="n">lb</span><span class="o">/</span><span class="n">viscous</span>
</pre></div>
</div>
<ul class="simple">
<li>ID, group-ID are documented in <a class="reference internal" href="fix.html"><span class="doc">fix</span></a> command</li>
<li>lb/viscous = style name of this fix command</li>
</ul>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<p>fix 1 flow lb/viscous</p>
</div>
<div class="section" id="description">
<h2>Description</h2>
<p>This fix is similar to the <a class="reference internal" href="fix_viscous.html"><span class="doc">fix viscous</span></a> command, and
is to be used in place of that command when a lattice-Boltzmann fluid
is present, and the user wishes to integrate the particle motion using
one of the built in LAMMPS integrators.</p>
<p>This fix adds a force, F = - Gamma*(velocity-fluid_velocity), to each
atom, where Gamma is the force coupling constant described in the <a class="reference internal" href="fix_lb_fluid.html"><span class="doc">fix lb/fluid</span></a> command (which applies an equal and
opposite force to the fluid).</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">This fix should only be used in conjunction with one of the
built in LAMMPS integrators; it should not be used with the <a class="reference internal" href="fix_lb_pc.html"><span class="doc">fix lb/pc</span></a> or <a class="reference internal" href="fix_lb_rigid_pc_sphere.html"><span class="doc">fix lb/rigid/pc/sphere</span></a> integrators, which
already include the hydrodynamic forces. These latter fixes should
only be used if the force coupling constant has been set by the user
(instead of using the default value); if the default force coupling
value is used, then this fix provides the only method for adding the
hydrodynamic forces to the particles.</p>
</div>
<hr class="docutils" />
<p>For further details, as well as descriptions and results of several
test runs, see <a class="reference internal" href="#mackay"><span class="std std-ref">Mackay et al.</span></a>. Please include a citation to
this paper if this fix is used in work contributing to published
research.</p>
</div>
<hr class="docutils" />
<div class="section" id="restart-fix-modify-output-run-start-stop-minimize-info">
<h2>Restart, fix_modify, output, run start/stop, minimize info</h2>
<p>As described in the <a class="reference internal" href="fix_viscous.html"><span class="doc">fix viscous</span></a> documentation:</p>
<p>&#8220;No information about this fix is written to <a class="reference internal" href="restart.html"><span class="doc">binary restart files</span></a>. None of the <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> options
are relevant to this fix. No global or per-atom quantities are stored
by this fix for access by various <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">output commands</span></a>. No parameter of this fix can
be used with the <em>start/stop</em> keywords of the <a class="reference internal" href="run.html"><span class="doc">run</span></a> command.</p>
<p>The forces due to this fix are imposed during an energy minimization,
invoked by the <a class="reference internal" href="minimize.html"><span class="doc">minimize</span></a> command. This fix should only
be used with damped dynamics minimizers that allow for
non-conservative forces. See the <a class="reference internal" href="min_style.html"><span class="doc">min_style</span></a> command
for details.&#8221;</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions</h2>
<p>This fix is part of the USER-LB package. It is only enabled if LAMMPS
was built with that package. See the <span class="xref std std-ref">Making LAMMPS</span> section for more info.</p>
<p>Can only be used if a lattice-Boltzmann fluid has been created via the
<a class="reference internal" href="fix_lb_fluid.html"><span class="doc">fix lb/fluid</span></a> command, and must come after this
command.</p>
<p>This fix should not be used if either the <a class="reference internal" href="fix_lb_pc.html"><span class="doc">fix lb/pc</span></a>
or <a class="reference internal" href="fix_lb_rigid_pc_sphere.html"><span class="doc">fix lb/rigid/pc/sphere</span></a> integrator is
used.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="fix_lb_fluid.html"><span class="doc">fix lb/fluid</span></a>, <a class="reference internal" href="fix_lb_pc.html"><span class="doc">fix lb/pc</span></a>, <a class="reference internal" href="fix_lb_rigid_pc_sphere.html"><span class="doc">fix lb/rigid/pc/sphere</span></a></p>
<p><strong>Default:</strong> none</p>
<hr class="docutils" />
<p id="mackay"><strong>(Mackay et al.)</strong> Mackay, F. E., Ollila, S.T.T., and Denniston, C., Hydrodynamic Forces Implemented into LAMMPS through a lattice-Boltzmann fluid, Computer Physics Communications 184 (2013) 2021-2031.</p>
</div>
</div>
</div>
</div>
<footer>
<hr/>
<div role="contentinfo">
<p>
&copy; Copyright 2013 Sandia Corporation.
</p>
</div>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT:'./',
VERSION:'',
COLLAPSE_INDEX:false,
FILE_SUFFIX:'.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/jquery-1.11.0.min.js"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/lightbox.min.js"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2-customize/jquery-noconflict.js"></script>
<script type="text/javascript" src="_static/js/theme.js"></script>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.StickyNav.enable();
});
</script>
</body>
</html>

Event Timeline

c4science · Help